﻿//-----------------------------------------------------
//	OurFAS 固定资产管理系统
//	Copyright (C) 2012  zealot team 
//  内容：外部类，枚举类型基类
//  时间: 2012-1-2
//  By：Apach Wendy
//-----------------------------------------------------
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Reflection;
using System.Collections;

namespace OurFAS.Data
{
    [AttributeUsage(AttributeTargets.Field | AttributeTargets.Enum)]
    public class EnumDescription : Attribute
    {
        private string enumDisplayText; private int enumRank;
        private FieldInfo fieldIno;
        /// <summary>        
        /// 描述枚举值      
        /// </summary>  
        /// <param name="enumDisplayText">描述内容</param>  
        /// /// <param name="enumRank">排列顺序</param>    
        public EnumDescription(string enumDisplayText, int enumRank)
        {
            this.enumDisplayText = enumDisplayText;
            this.enumRank = enumRank;
        }
        /// <summary>      
        /// 描述枚举值，默认排序为5   
        /// </summary>       
        /// <param name="enumDisplayText">描述内容</param>      
        public EnumDescription(string enumDisplayText) : this(enumDisplayText, 5) { }
        public string EnumDisplayText
        {
            get
            {
                return this.enumDisplayText;
            }
        }
        public int EnumRank
        {
            get
            {
                return enumRank;
            }
        }
        public int EnumValue
        {
            get
            {
                return (int)fieldIno.GetValue(null);
            }
        }
        public string FieldName
        {
            get
            {
                return fieldIno.Name;
            }
        }
        #region  =========================================对枚举描述属性的解释相关函数
        /// <summary>       
        /// /// 排序类型      
        /// /// </summary>       
        public enum SortType
        {
            /// <summary>         
            ///按枚举顺序默认排序  
            /// </summary>         
            Default,
            /// <summary>            
            /// 按描述值排序            
            /// </summary>            
            DisplayText,
            /// <summary>            
            /// 按排序熵            
            /// </summary>            
            Rank
        }         private static System.Collections.Hashtable cachedEnum = new Hashtable();
        /// <summary>        
        /// 得到对枚举的描述文本        
        /// </summary>        
        /// <param name="enumType">枚举类型</param>        
        /// <returns></returns>     
        public static string GetEnumText(Type enumType) { EnumDescription[] eds = (EnumDescription[])enumType.GetCustomAttributes(typeof(EnumDescription), false); if (eds.Length != 1) return string.Empty; return eds[0].EnumDisplayText; }
        /// <summary>        
        /// 获得指定枚举类型中，指定值的描述文本。        
        /// </summary>        
        /// <param name="enumValue">枚举值，不要作任何类型转换</param>        
        /// <returns>描述字符串</returns>       
        public static string GetFieldText(object enumValue) { EnumDescription[] descriptions = GetFieldTexts(enumValue.GetType(), SortType.Default); foreach (EnumDescription ed in descriptions) { if (ed.fieldIno.Name == enumValue.ToString()) return ed.EnumDisplayText; } return string.Empty; }
        /// <summary>        
        /// 得到枚举类型定义的所有文本，按定义的顺序返回        
        /// </summary>        
        /// <exception cref="NotSupportedException"></exception>        
        /// <param name="enumType">枚举类型</param>        
        /// <returns>所有定义的文本</returns>        
        public static EnumDescription[] GetFieldTexts(Type enumType)
        {
            return GetFieldTexts(enumType, SortType.Default);
        }
        /// <summary>        
        /// 得到枚举类型定义的所有文本        
        /// </summary>        
        /// <exception cref="NotSupportedException"></exception>        
        /// <param name="enumType">枚举类型</param>        /// <param name="sortType">指定排序类型</param>        /// <returns>所有定义的文本</returns>        
        public static EnumDescription[] GetFieldTexts(Type enumType, SortType sortType)
        {
            EnumDescription[] descriptions = null;
            //缓存中没有找到，通过反射获得字段的描述信息           
            if (cachedEnum.Contains(enumType.FullName) == false)
            {
                FieldInfo[] fields = enumType.GetFields();
                ArrayList edAL = new ArrayList();
                foreach (FieldInfo fi in fields)
                {
                    object[] eds = fi.GetCustomAttributes(typeof(EnumDescription), false);
                    if (eds.Length != 1)
                        continue;
                    ((EnumDescription)eds[0]).fieldIno = fi;
                    edAL.Add(eds[0]);
                }
                cachedEnum.Add(enumType.FullName, (EnumDescription[])edAL.ToArray(typeof(EnumDescription)));
            }
            descriptions = (EnumDescription[])cachedEnum[enumType.FullName];
            if (descriptions.Length <= 0)
                throw new NotSupportedException("枚举类型[" + enumType.Name + "]未定义属性EnumValueDescription");
            //按指定的属性冒泡排序            
            for (int m = 0; m < descriptions.Length; m++)
            {
                //默认就不排序了         
                if (sortType == SortType.Default) break;
                for (int n = m; n < descriptions.Length; n++)
                {
                    EnumDescription temp;
                    bool swap = false;
                    switch (sortType)
                    {
                        case SortType.Default:
                            break;
                        case SortType.DisplayText:
                            if (string.Compare(descriptions[m].EnumDisplayText, descriptions[n].EnumDisplayText) > 0)
                                swap = true;
                            break;
                        case SortType.Rank:
                            if (descriptions[m].EnumRank > descriptions[n].EnumRank) swap = true; break;
                    }
                    if (swap)
                    {
                        temp = descriptions[m];
                        descriptions[m] = descriptions[n];
                        descriptions[n] = temp;
                    }
                }
            }
            return descriptions;
        }
        #endregion
    }
}
